Airlines were seeing a travel rebound before Omicron arrived.

The discovery the Omicron variant comes at a delicate moment for an airline industry that was just starting to see a rebound.

The question is whether the new coronavirus variant will deter travelers, as the Delta variant did this summer.

Several nations, including the United States, have banned visitors from South Africa and a handful of neighboring countries. Morocco has banned all incoming flights for two weeks, the Philippines has banned visitors from southern Africa and several European countries, and Israel has closed its borders to all foreign visitors for 14 days.

The international travel recovery has been slower than it has been in the United States. President Biden’s decision to ease longstanding restrictions on foreign travelers this month promised to stimulate that rebound. It isn’t yet clear how or whether the Omicron variant will affect travel demand, but if travel bans proliferate and concerns over the variant continue to spread, hopes for an accelerated international rebound could be dashed once again.

Only two U.S. carriers, Delta Air Lines and United Airlines, fly out of southern Africa. Both have said that they are not yet planning to adjust their schedules in response to the administration’s ban, which takes effect on Monday and does not apply to American citizens or lawful permanent residents. Delta operates three weekly flights between Atlanta and Johannesburg. United operates five flights a week between Newark and Johannesburg, and it has not changed its plans to restart flights between Newark and Cape Town on Wednesday. None of the countries that have announced the new travel restrictions are major sources of business for U.S. carriers.

No major American airline has announced any substantive changes to procedures because of the variant. And all passengers flying into the United States must provide proof of a negative coronavirus test, with noncitizens also required to be fully vaccinated.

Within the United States, air travel has nearly recovered, even with many businesses still wary of sending employees on work trips. The number of people screened at airport security checkpoints over the past week was down only 10 percent from the same week in 2019, according to the Transportation Security Administration. And the industry successfully weathered the crush of travelers, avoiding the disruptions that at some airlines lasted for days in recent months.